Port workers believe the application from a container ship to enter the Port of Tauranga under the condition no contagious disease was on board was not done in good faith, a Union spokeswoman says.
The comment comes as the Rio de la Plata departed New Zealand, en route to Malaysia.
The vessel was originally planned to stop at Napier before 11 of the 21 crew tested positive for Covid-19.
Despite this, the Ministry of Health stated the risk to the Tauranga community remained low.
Ships entering any harbour are obligated to declare they are free of contagious disease - it is referred to as the "free pratique" process.
Ships must apply to the local Medical Officer of Health for permission to berth before entering any port, however, port workers believed this was not done in good faith, Rail and Maritime Transport Union Central North Island organiser Dasha Van Silfhout said.
"Another question is whether the officials knew and didn't supply the right information, or whether they didn't know - these are all the questions the members are asking but not being answered."
All tests from the Rio de la Plata outbreak had returned negative results aside from six that were outstanding, Covid-19 Response Minister Chris Hipkins said at yesterday's briefing.
Port of Tauranga spokeswoman Rochelle Lockley said it was a big relief for all involved.
"Many of the stevedores involved have been cleared to return to work and operations at the container terminal are expected to ramp up from tonight.
"There will be some ongoing delays while we recover, but safety is our overriding concern."
However, Van Silfhout said workers were still stressed and had many questions that were unanswered.
She said the company in question had been good at communicating with the port workers, but it was government agencies that had let workers down.
"Our members have questions that the company can't answer. So the frustration is very much centred at the government agencies, or the higher level, that allows the vessel to dock and be shut down and then restart."
Questions the workers had included, who gave the authority and who can give the authority.
"They are wondering how we, and I'm not sure who we is, allowed this to happen and why wasn't there a clear process put in place.
"They are just not getting the answers because the company doesn't know."
The Bay of Plenty Times understood port workers were considering a meeting to discuss industrial action. Dasha said she had not heard anything, so could not confirm if this was true.
"But it could be a possibility."
Port operations were initially shut down last week when cargo left the vessel, despite the Ministry of Health giving the all-clear for operations, Maritime NZ confirmed to the Bay of Plenty Times on Tuesday.
The Ministry of Health said Rio de la Plata crew were tested on Saturday morning.
"In this particular instance, based on the information provided by Australian authorities, an additional specific analysis was done around whether the Queensland pilot could have bought Covid on board the vessel," a spokesman said.
"As a result, the health assessment remained the same – namely that the arriving Rio de la Plata ship could have Covid-19 cases on board, and would be treated as such."
The Ministry of Health was approached for comment in relation to the comments made by the union, but could not respond by deadline and referred the Bay of Plenty Times to an earlier press release.
"As is standard practice with the Covid-19 response, the ministry is reviewing the incident response over the next few days and will be providing an initial update to the minister early next week on lessons and improvements," it said in the written statement.
"In addition, a fuller review process will also incorporate the three other recent incidents involving the vessels the Playa Zahara, the Viking Bay and the Mattina with infected crew."
Tauranga National MP Simon Bridges said he would hate to see the region being the next location for a Covid-19 outbreak and believed the message was clear; vaccinate.
"I strongly urge them to get on with it because otherwise our entire city, and possibly our region, is at risk.
"The worst-case scenario is another lockdown."
The risk of a Delta outbreak meant the Ministry of Health was reassessing New Zealand's outbreak, Hipkins said yesterday.
The adjustment meant - if there was a case of an outbreak - New Zealand would likely see a quicker move to level 4.
A "short sharp lockdown" was preferable to a drawn-out response, he said.
The Rio de la Plata
• The Rio de la Plata is a container ship. The cargo exchanged at Tauranga was mostly import containers containing a wide range of goods including food, medical supplies, consumer items , etc.